opencv: invalidate Nix store paths used in version_string.inc (#444123)

pkgs/development/libraries/opencv/0001-cmake-OpenCVUtils.cmake-invalidate-Nix-store-paths-b.patch

@@ -0,0 +1,34 @@
+From fcc689e1887bcbeb9d1c4441266a63ea2114ae9f Mon Sep 17 00:00:00 2001
+From: Connor Baker <ConnorBaker01@gmail.com>
+Date: Thu, 18 Sep 2025 13:15:43 -0700
+Subject: [PATCH] cmake/OpenCVUtils.cmake: invalidate Nix store paths before
+ including in version_string.inc
+
+Signed-off-by: Connor Baker <ConnorBaker01@gmail.com>
+---
+ cmake/OpenCVUtils.cmake | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+diff --git a/cmake/OpenCVUtils.cmake b/cmake/OpenCVUtils.cmake
+index 5886f4f3cb..9f3a3a74e9 100644
+--- a/cmake/OpenCVUtils.cmake
++++ b/cmake/OpenCVUtils.cmake
+@@ -956,6 +956,15 @@ function(ocv_output_status msg)
+     message(WARNING "String to be inserted to version_string.inc has an unexpected line break: '${msg}'")
+     string(REPLACE "\n" "\\n" msg "${msg}")
+   endif()
++  # The hash portion of Nix store paths are 32 characters long. Replace them with an invalid hash to avoid bloating
++  # the runtime closure by includnig references to the compiler and other build tools.
++  # https://fzakaria.com/2025/03/28/what-s-in-a-nix-store-path
++  # NOTE: This assumes the name of the Nix store is always /nix/store.
++  # NOTE: The regex [a-z0-9] is larger than Nix's base32, but it simplifies things.
++  # NOTE: This assumes all Nix store paths have additional characters after the hash.
++  # NOTE: CMake doesn't support fixed-length matching. See:
++  # https://cmake.org/cmake/help/latest/command/string.html#regex-specification
++  string(REGEX REPLACE "/nix/store/[a-z0-9]+-" "/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-" msg "${msg}")
+   set(OPENCV_BUILD_INFO_STR "${OPENCV_BUILD_INFO_STR}\"${msg}\\n\"\n" CACHE INTERNAL "")
+ endfunction()
+ 
+-- 
+2.48.1
+

pkgs/development/libraries/opencv/4.x.nix

@@ -298,6 +298,7 @@ effectiveStdenv.mkDerivation {
   # Ensures that we use the system OpenEXR rather than the vendored copy of the source included with OpenCV.
   patches = [
     ./cmake-don-t-use-OpenCVFindOpenEXR.patch
+    ./0001-cmake-OpenCVUtils.cmake-invalidate-Nix-store-paths-b.patch
   ]
   ++ optionals enableCuda [
     ./cuda_opt_flow.patch
@@ -321,11 +322,6 @@ effectiveStdenv.mkDerivation {
       ${installExtraFiles wechat_qrcode}
     '');
 
-  postConfigure = ''
-    [ -e modules/core/version_string.inc ]
-    echo '"(build info elided)"' > modules/core/version_string.inc
-  '';
-
   buildInputs = [
     boost
     gflags